/**
 * Copyright 2000 self.com.au
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. (http://www.apache.org/licenses/LICENSE-2.0)
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed 
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for 
 * the specific language governing permissions and limitations under the License.
 *
 * <dhamma-message src="Atisha (11th century Tibetan Buddhist master)">
 * 	The greatest achievement is selflessness. The greatest worth is self-mastery.
 * 	The greatest quality is seeking to serve others. The greatest precept is continual awareness.
 * 	The greatest medicine is the emptiness of everything. The greatest action is not conforming with the worlds ways.
 * 	The greatest magic is transmuting the passions. The greatest generosity is non-attachment.
 * 	The greatest goodness is a peaceful mind. The greatest patience is humility.
 * 	The greatest effort is not concerned with results. The greatest meditation is a mind that lets go.
 * 	The greatest wisdom is seeing through appearances. 
 * </dhamma-message>
 *
 * @author Ashin Wimalajeewa
 */
package self.amigo.translator;

import java.io.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;

import self.xml.*;

abstract public class ABasicSaxBasedTranslator implements ITranslator {
  private DefaultHandler handler;
  
  public ABasicSaxBasedTranslator() {
    handler = createHandler();
  }
  
  protected DefaultHandler createHandler() {
    return new ExpressVerifier();
  }
  
  protected class UValidTypeExpressExit extends RuntimeException {
  	
	/**
	 * If the internal state of this class ever changes in such a way that it can't be defaulted,
	 * then the {@link #serialVersionUID} should be incremented to ensure serialized instances cleanly fail.  
	 */
	private static final long serialVersionUID = 1;
	
    public UValidTypeExpressExit( String s ) {
      super( "UValidTypeExpressExit::" + s );
    }
  }
  
  public boolean  canHandle( Reader data ) {
    if ( handler instanceof ExpressVerifier )
      ((ExpressVerifier)handler).reset();
    XMLReader xmlReader = SaxUtils.getXmlReader();
    xmlReader.setContentHandler( handler );
    xmlReader.setEntityResolver( handler );
    try {
      InputSource src = new InputSource( data );
      xmlReader.parse( src );     
    } catch ( Exception err ) {
      String errMsg = err.getMessage();
      int expressPos = errMsg.indexOf( "UValidTypeExpressExit" );
      if ( expressPos > -1 )
        return true;
      return false;
    }
    return false;
  }
  
  abstract protected void checkDocument( String name, Attributes attrs );
  
  protected class ExpressVerifier extends DefaultHandler {
    public  boolean ok = false;
    private int     count = 0;
    
    public void reset() {
      ok = false;
      count = 0;
    }
    
    public InputSource resolveEntity(String p0, String p1) throws SAXException { 
      return new InputSource( new StringReader("") );
    }
    
    public void startElement( java.lang.String uri, java.lang.String localName, java.lang.String qName, Attributes attrs )   {
      if ( ok )
        return;
      if ( count > 0 )
        throw new IllegalStateException( "err.aid.translator.express_verification" );
      count++;
      checkDocument( localName, attrs );
    }
  }
}
